44 R. BULLEN NEWTON on 



the surface of the sutural platform is radially costated ; extremely fine longi- 

 tudinal, close, microscopical striations enter, also, into the sculpture of the 

 shell. 



DIMENSIONS. 



Alt. ... ... ... ... ... ... ... 10 millimetres 



Lat ... 6 



REMARKS. This small and highly ornamented shell, of which there are only 

 three specimens, forms an excellent example of De Blainville's Trigonostoma, 1 

 (type = Delphinula trigonostoma^ Deshayes), sharing most of its characters, but 

 bearing only the slightest evidence of an umbilicus instead of the prominent 

 basal cavity which is so significant of the type, a recent shell from Ceylon seas. 

 It is interesting to observe that among fossil forms the new shell exhibits closest 

 affinities with Cancellaria (Trigonostoma} propegemmata of De Gregorio 2 from 

 the Eocene deposits of Alabama, especially in size, contour, and the very 

 restricted character of the umbilicus. The sculpture, however, is less com- 

 plicated in the American shell, where the costae are of one order only and 

 considerably less inflated, while the spinose sutural margins are much more 

 regular, and moreover there is a lack of definition about the transverse striations 

 which appear to be almost obsolete. This Cancellariform shell is apparently 

 unknown in the European Eocene fauna, nothing similar having been noticed by 

 M. Cossmann 3 in his analysis of Trigonostoma. 



OCCURRENCE. Cutting No. 6. 

 COLLECTOR. Mr. Kitson. 



Bonellitia cf. evulsa (Solander). 



PLATE 5, figs. 14, 15. 

 Buccimim evulsum. 



Solander: Brander's " Fossilia Hantoniensia," 1766, pi. i, fig. 14, p. 13. 

 Cancellaria evulsa. 



J. de C. Sowerby : Mineral Conchology, 1822, Vol. 4, pi. 361, figs. 2-4, p. 84. 

 Bonellitia evulsa. 



Jousseaume : Le Naturaliste, 1887, Ser. 2, Vol. I, p. 223 ; Cossmann : Essais Paleoconch, Comp., 

 1899 ; Vol. 3, pp. 32-34. 



REMARKS. It is difficult to separate this Cancellariform shell from the well 

 known B^lccinum eviilsum of Solander, belonging to the Bracklesham and 



1 Manuel Malacologie. 1825, p. 652. 



a Ann. G^ol. Pal. (Palermo), 1890, part 7., p. 46, pi. 3, figs. 14, 15. 



3 Essais Paleoconchologie Comp., 1899, part 3, pp. 24-26. 



